The proposed research focuses on the development of a compact, integrated high-field EPR spectrometer for DNP-enhanced solid-state, magic-angle-spinning (MAS) NMR spectroscopy. The spectrometer will allow researchers to record the EPR spectra and obtain valuable relaxation parameters of the DNP sample under the same conditions under which the DNP experiment is performed. In recent years, DNP has proven to be a robust method to increase signal intensities in NMR experiments in laboratories around the world and substantial progress has been made in adapting DNP for solid-state NMR spectroscopy. However, to understand and optimize the DNP process it is crucial to fully understand the EPR spectrum and relaxation parameters of the polarizing agent. Only a few home-built high-field spectrometers are available around the world. Therefore researchers often have to speculate about the EPR characteristics of their DNP sample. We propose to develop a cost-effective EPR spectrometer that can easily be adapted to cover the complete frequency range that is currently used in DNP spectroscopy. The design will be compact and turn-key so that the device can also be used by non experts. During Phase I of this project we will perform the complete mechanical and electrical design and fabricate a prototype EPR spectrometer operating at 263 GHz (400 MHz 1H). The successful development of this technology will provide researchers access to currently inaccessible EPR characteristics and will proliferate the development of new, optimized polarizing agents for DNP-NMR spectroscopy. This will be of large interest to many projects funded by the U.S. National Institutes of Health.